United boss Carrick faced mounting pressure after a poor run of three draws and three defeats in all competitions sealed their worst start to a league campaign for 40 years.

But a lacklustre Red Devils team failed to muster a response in the wind and rain of northern Italy as they were thoroughly outclassed to remain on three points in the Champions League.

Cesc Fabregas's side have enjoyed a fairytale rise from Serie B to Europe's elite club competition over the last three years, but their dismantling of the three-time European champions will go down as one of the greatest results in club history.

Argentina international Paz lit up the Stadio Giuseppe Sinigaglia with superb solo efforts either side of Douvikas's accomplished finish, before Ramon's header completed the rout as Como claimed their second win of the league phase to move up to six points.

With both sides facing a string of injuries, there was one major surprise in Carrick's team as defender Matthijs de Ligt returned for his first appearance in 11 months following injury, replacing the suspended Leny Yoro.

Diogo Dalot had an early sight at goal when his shot curled inches wide of the far post, but Como immediately went up the other end and showed superior cutting edge.

- Familiar flaws exposed -

Paz received the ball on the edge of the box, shifted it onto his favoured left foot and guided a finish home to give the hosts a dream start inside two minutes.

It exposed familiar flaws for United, who conceded inside the opening minute in their 2-0 defeat to Atletico Madrid last week and have now kept one clean sheet in 11 games this season in all competitions.

Como's confidence grew with the lead as they dominated possession and restricted rudderless United to having no shots on target before half-time, while threatening themselves through Douvikas and Martin Baturina.

Carrick made a double change at the interval to try and lift a sluggish performance as Amad Diallo and Carlos Baleba replaced Andrey Santos and Matheus Cunha.

But they were caught cold once again as Paz slipped a through ball into Douvikas's path and the Greece international lifted a first-time finish into the top corner three minutes into the second half.

Como captain Lucas Da Cunha squandered a promising chance to make it three by shooting wide.

But the home crowd did not have to wait long to celebrate again as Paz nicked the ball off a hesitant Baleba in midfield before driving forward and finishing coolly in the 57th minute.

A shell-shocked United defence almost conceded a fourth when Paz, eyeing a hat-trick, had a curling effort saved by a diving Senne Lammens.

Number four arrived with 14 minutes to go when unmarked centre-back Ramon roamed forward to head home an inviting cross.

It sparked an exodus of fans in the away end, who missed substitute Zirkzee's stoppage-time strike in United's one bright moment of the evening.